Twitter is a great place to say stupid shit. Worst case scenario is that you look like an idiot. In China, things are a bit different; thousands of censors trawl the nation's Twitter-clone Weibo, quashing pesky dissent with lightning reflexes. And though China doesn't share its methods, computer scientists have been able to figure out just how the wildly efficient the process must be.

Wiebo has some 300 million users who send roughly 100 million messages a day between them. That's about 70,000 messages per minute. By observing a sample of 3500 posters who, between them, had about 4500 posts censored over 15 days, Dan Wallach of Rice University in Houston, Texas and his partners were able to uncover the true, blinding speed of China's censorship.

Thirty percent of the heretical tweets manage to be censored within the minute they are pushed out, and 90 percent within the day. That's impressive, but it only gets better (worse?) when you calculate what that censor-force must look like. According to Wallach's calculations:

If an average censor can scan around 50 posts a minute, that would require some 1400 censors at any instant to handle the 70,000 posts pouring in. And if they work 8 hour shifts, that's a total of 4200 censors on the payroll each day.

Surely they must have help, keyword alerts, lists of trouble-posters, auto-blocked phrases like "Secretary of the Political and Legislative Committee" for some reason, etc, but it's clear that China is putting some serious effort into scrubbing Weibo clean in real time instead of delaying posts, or shutting down the service all together. It just goes to show you can do anything you put your mind to, especially if you're an authoritarian government hell-bent on the continued suppression of free speech. Hooray. [MIT Technology Review]